1. Field of the Invention
The present invention relates to dicing blades and, more particularly, to an enhanced composition of a dicing blade for providing increased strength, cutting capability and accuracy.
2. Description of the Related Art
Wafer saws having dicing blades have been used by the semiconductor industry for decades to cut or dice substrates, often referred to as wafers, into separate pieces or die. Numerous manufacturers provide such wafer saws to the industry. Typically, the wafer saw includes an aluminum hub mountable upon a rotatable spindle. The dicing blade is in the nature of a radially oriented annular band plated to the peripheral radial side of the hub. It extends past the perimeter of the hub. A wafer saw having a dicing blade of this type is disclosed and described in U.S. Pat. No. 3,691,707.
Construction of the dicing blade begins with a formed aluminum hub mounted upon a titanium mandrel. An O-ring seal or the like is placed adjacent the hub radially interiorly from the perimeter to serve as a mask and permits selective plating only on the annular area where the dicing blade is to be formed. The plating tank includes a nickel plating solution having diamond particles suspended therein. The nickel plating solution may be a nickel sulfamate solution sold under various trademarks, such as Allied Kelite, Enthone, SelRex, etc. The diamond particles or abrasive grit is usually sized in the range of two to eight microns. It is maintained in suspension by either mechanical or air agitation. The nickel plating tank may be of various configurations (round, square, etc.). The nickel plating solution is heated to operating temperature by using immersion heaters and automatic temperature controls to maintain a preset temperature to plus or minus two percent. Pure nickel anodes are located within the tank and at an equal spacing about the hub supporting mandrel (cathode). The power or current from a DC power supply is regulated to a current density (amperes per square foot of plating area) suggested by the supplier of the plating solution.
The mandrel, containing one or more hubs, is rotated at a preselected speed for a predetermined duration. Rotation is thereafter stopped to permit the diamond particles to settle on the exposed annular hub area. Rotation is subsequently reversed and then stopped. This cycle is repeated until a desired thickness of nickel and diamond particle composition is reached. Generally, the deposition rate of nickel sulfamate is approximately 0.001 inches (25.4 mm) per hour.
The presently available conventional dicing saw blades produced in accordance with the above described process, or variants thereof, provide a length of cut of wafers in the range of 10,000 to 15,000 inches with a radial wear of the dicing blade in the range of 3 to 5 mils. The thickness of the blades range from approximately 0.6 mil to 4 mils and the kerf formed in the wafer is approximately 1.2 times the thickness of the blade. The additional thickness of the kerf over that of the blade is generally attributed to a certain amount of wobble that occurs. Because of such wobble, the structural integrity of the blade is compromised. To reduce the probability of a ruined wafer as a result of a broken or shattered dicing blade, it is an industry wide standard procedure to discard the dicing blades after 5,000 to 15,000 inches of cut.